In a burst frame system, after receiving a signal, a receiving end performs automatic gain control on the signal, and the gain refers to signal power magnification. The burst frame system can provide a cyclic prefix mechanism or similar mechanisms, that is, the signal received by the receiving end includes a cyclic prefix signal, where the cyclic prefix signal can enable the receiving end to learn that a data signal is coming.
The receiving end receives frames at unfixed intervals and a power fluctuation range of the received signal is large and changes frequently, so that requirements on the automatic gain control for the receiving end are high. The receiving end is required to realize signal power magnification when the signal is coming to enable the signal power to be close to target power and subsequent modules are supported in working normally. However, in the prior art, because of limitation of A/D (Analog to Digital Converter, where an analog signal is converted to a digital signal) bit bandwidth, the receiving end is incapable of realizing signal power magnification accurately.